Fresh and mechanical properties of roller compacted concrete containing Cationic Asphalt Emulsion admixture

Abstract

This research aims at evaluating the fresh and mechanical properties of RCC mixtures containing Cationic Asphalt Emulsion -CAE- as an admixture -0%, 2%, 4%, 6%, 8%, and 10% of the cement mass-. Mixtures’ proportions were obtained for each RCC mixture by calculating the maximum value on moisture-dry density curve according to modified proctor method. Then, Optimum Moisture Contents -OMC- and Maximum Dry Densities -MDD- were compared among the mixtures. Fresh properties of the RCC mixtures were also evaluated by Superpave Gyratory Compactor -SGC- while compressive strength, splitting tensile strength and flexural strength tests were employed for investigating the mechanical properties of the mixtures. Non-destructive ultrasonic test was performed in each cubic specimen to develop the compressive strength estimation model. Significance of the results’ difference in each test considering the CAE content and curing age as sources of variance was assessed through Analysis of Variance -ANOVA- at 95% confidence level. Results indicated a significant improvement in fresh properties, and a significant drop in the mechanical properties when CAE is used as an admixture. In addition, Scanning Electron Microscope -SEM- images were used to evaluate the micro-structure of the mixtures. Results of this research indicate that 4% of CAE can reduce the amount of compaction energy required to reach the satisfactory field density. This improvement in fresh properties can decrease execution costs and lead to time saving. Furthermore, results of the mechanical tests indicate a reduction in mixture strengths due to the decreased cohesion between cement paste and the asphalt covered aggregates.